A type of domestically grown genetically modified dairy cow resistant to an infection that lowers milk yield is expected to reach the market in five to eight years, according to a national legislator.

The bacterial infection, mastitis, is widespread among dairy cattle.

Sun Qixin, president of Northwest Agriculture and Forestry University and a National People's Congress deputy, said the university has been researching a GM cow for seven years.

"It's now being tested for its safety in human food products and in the environment," Sun said.

Professor Zhang Yong of the veterinary medicine department at the university, who is in charge of the research, said, "We've fed laboratory mice milk from the genetically engineered cow for five generations and so far nothing wrong has been detected in the mice. That's highly promising."

But he said even if everything goes smoothly, such a cow still needs to pass many regulatory hurdles and the test of public opinion before becoming a commercial prospect.

Zhang said the university now keeps more than 100 such cattle, which have been examined and observed closely for any potential health and growth problems.

So far, "they have been doing pretty well," he said.

Apart from laboratory mice, "we also feed other cattle with GM cow milk and so far everything has been fine with the recipients," he said.

All food from genetically modified organisms, both crops and animals, must undergo a series of strict safety assessments and examinations before being ready for human consumption, he said.

The safety testing alone usually takes at least three years, he added.

For the type of GM cow they have been researching, Zhang said the protein of the genes used is from human milk and saliva. And the genes have never resulted in any negative health impact.

Thereafter, in theory, "it should be safe for the cow itself and humans who consume related food products." But he said each step of the research process is, as required by national regulations, scrutinized and managed closely.

Sun said the move is a definite future trend but it is important to ensure safety as well.

He said China trails other countries in research and commercialization of GM animals.

"We can genetically alter animals to make them resistant to diseases like foot-and-mouth disease, bird flu and swine fever to avert big losses for the animal-raising industry," he said.

"The technology should be widely applied primarily in the nation's stockbreeding industry."

Sun said there has been plenty of international research into GM animals, mainly for purposes such as improved animal breeding for food consumption, resistance to certain animal diseases, and to improve feeding efficiency.

But so far, no GM animals or animal products have been sold for food, although some drugs in use are made from transgenic animals.

The latest example is a type of salmon in the United States that contains genes from two other fish species to enable it to grow faster.

But the fish has yet to be approved by the US food safety authority, and there are also public concerns about its safety.

In China, the public debate over the safety of GM food products — mostly crops — continues and many people remain concerned about potential health impacts from long-term consumption.

However, some of the products have already appeared on supermarket shelves in many parts of the world, according to Huang Dafang, a researcher at the Biotechnology Research Institute under the Chinese Academy of Agricultural Sciences.

He said the Chinese, including the current minister of agriculture, have been consuming soybean oil from genetically modified organisms.

Worldwide, the US started to introduce GMO food to the dining table in 1996 and so far 28 countries have planted GM crops, Huang added.

In Beijing, a housewife surnamed Cui said she prefers natural food and will not shop for GM soybean oil.

"It takes a long time to draw a conclusion on whether it's safe or not to eat, so I won't try it on my family members," she said.